In communication networks, such as telecommunication networks, a call or a service often involves, on the one hand, a control plane or signalling plane and, on the other hand, a user plane or media plane. The control plane or signalling plane is concerned with connection management. The user plane or media plane is mainly in charge of transporting the user data.
In this context, network operators often want to define and enforce a set of rules in the network. A set of rules constitutes policies. A policy framework for managing and enforcing these policies usually includes at least three elements, or functions: a policy repository for storing the policy rules, which may be user-specific, a policy decision element, function or point, and a policy enforcement element, function or point. The purposes of a policy framework include controlling subscriber access to the networks and services.
A policy framework notably addresses the decisions as to whether the subscriber, i.e. the user, is entitled, or authorized, to enjoy a service, and whether the network can provide the service to the subscriber (and, possibly, with which quality of service).
PCC architectures, such as, but not limited to, the architecture described in “3GPP TS 23.203 V11.9.0 (2013-03); Technical Specification; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Policy and charging control architecture (Release 11)” (available from 3gpp.org) (Hereinafter referred to as “reference [1]”), integrate the policy and charging control.
In such a PCC architecture, the policy and charging rules function (PCRF) is a functional entity in charge of deciding charging, policies and quality of service (QoS) for services of a given user. The PCRF may for example decide the quality of the connection to be allocated for voice, video, etc., which results, for example, on the establishment of dedicated bearer(s) with guaranteed bit rate (GBR) or non-guaranteed bit rate (non GBR). The PCRF may also make decisions about packet forwarding treatment in the radio access network (RAN) by means of determining the QoS class identifier (QCI). The PCRF may also decide, at the packet core control plane, the priority of a bearer to be established over other bearers, for the same or different users. Based on the above decisions by the PCRF. PCC rules may be generated and than installed in a policy and charging enforcement function (PCEF) of the PCC architecture, so that each service is given the appropriate treatment that the service requires. Installing PCC rules from the PCRF in the PCEF may include the PCRF generating the PCC rules, downloading and activating said PCC rules to the PCEF, or may include activating, from the PCRF, indicated PCC rules configured in the PCEF.
It is known to let a service provider sponsor the data connectivity of a user with a limited data plan, in order to allow the user to access the service provider's services (see reference [1], Annex N, “PCC usage for sponsored data connectivity”; and document S2-095087, “Policy enhancement for dynamic data usage”, 3GPP TSG SA WG2 Meeting #75, 31 Aug.-4 Sep. 2009, Kyoto, Japan).
The prior art also includes WO 2010/133251 A1, relating to a method of operating an IP Multimedia Subsystem Application Server to facilitate a communication session between a first and second user at a required QoS. A notification is received that a PCRF associated with the first user has not authorised the required QoS. An authorisation is then requested, from a PCRF associated with the second user, for an additional QoS for the first user, and a notification is received that the PCRF associated with the second user has authorised the additional QoS. Eventually, the PCRF associated with the first user is notified that the additional QoS has been authorised for the first user. As a result, a session communication between the first and second user can be successfully established even if the QoS available to the first user is insufficient/inadequate for a particular session.
It is desirable to improve PCC architectures, notably by facilitating the provisions of services requiring data connectivity between users, especially between users with limited data plans, without increasing, or at least without excessively increasing, the implementation and architecture complexity and the associated equipment costs.